With reference to FIGS. 1-3, a conventional eccentric gear assembly, shown generally indicated at 10, is typically used in motors for window lift drive systems of vehicles for moving a window upwardly and downwardly. The eccentric gear assembly 10 includes an external gear or drive member 12 and a meshing internal gear or shaft member 14.
To move the drive member 12, a base member 16 is coupled with the drive member 12. FIGS. 2a-2d show that by sequentially moving the base member 16 in the X and Y directions by electro-mechanical actuators 18, the base member 16 will move in an orbiting manner (e.g., have circular displacement). U.S. Pat. No. 6,441,536 and U.S. Pat. No. 6,664,710 show motors employing electro-mechanical actuators to move such a drive member that surrounds a shaft member. Orbiting movement of the base member 12 generates rotational motion of the eccentric gear assembly 10.
FIGS. 3a to 3d represent in plan view instantaneous pictures for various phase angles (wt) of the shaft member 14 and the drive member 12 of the conventional eccentric gear assembly 10: (ωt)=0° and 360° in FIG. 3a, (ωt)=90° in FIG. 3b, (ωt)=180° in FIG. 3c, and (ωt)=270° in FIG. 3d. The arrows indicate the instantaneous direction of movement, that is to say the direction of the velocity vectors of the shaft member 14 and drive member 12. The angle Φk of the point Pk perpendicular to the longitudinal axis at which the shaft member 14 is instantaneously in contact with the drive member 14 (“contact point”) is yielded in accordance with: Φk=−ω*t.
Conventional, grounded leading pins 20 can be optionally employed to control (limit) amplitude of orbiting movement of the eccentric gear assembly 10.
There is a need to be able to cause motion of an eccentric gear assembly without using conventional electro-mechanical actuators.